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From:   Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To:     Mike Kravetz <mike.kravetz@oracle.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Michal Hocko <mhocko@kernel.org>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2 0/2] A couple hugetlbfs fixes
Thread-Topic: [PATCH v2 0/2] A couple hugetlbfs fixes
Thread-Index: AQHU6d4rcfOiD6QCGkOryDRCw26i8w==
Date:   Wed, 3 Apr 2019 05:29:12 +0000
Message-ID: <20190403052913.GA10888@hori.linux.bs1.fc.nec.co.jp>
References: <20190328234704.27083-1-mike.kravetz@oracle.com>
In-Reply-To: <20190328234704.27083-1-mike.kravetz@oracle.com>
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On Thu, Mar 28, 2019 at 04:47:02PM -0700, Mike Kravetz wrote:
> I stumbled on these two hugetlbfs issues while looking at other things:
> - The 'restore reserve' functionality at page free time should not
>   be adjusting subpool counts.
> - A BUG can be triggered (not easily) due to temporarily mapping a
>   page before doing a COW.
> 
> Both are described in detail in the commit message of the patches.
> I would appreciate comments from Davidlohr Bueso as one patch is
> directly related to code he added in commit 8382d914ebf7.
> 
> I did not cc stable as the first problem has been around since reserves
> were added to hugetlbfs and nobody has noticed.  The second is very hard
> to hit/reproduce.
> 
> v2 - Update definition and all callers of hugetlb_fault_mutex_hash as
>      the arguments mm and vma are no longer used or necessary.
> 
> Mike Kravetz (2):
>   huegtlbfs: on restore reserve error path retain subpool reservation
>   hugetlb: use same fault hash key for shared and private mappings
> 
>  fs/hugetlbfs/inode.c    |  7 ++-----
>  include/linux/hugetlb.h |  4 +---
>  mm/hugetlb.c            | 43 +++++++++++++++++++++--------------------
>  mm/userfaultfd.c        |  3 +--
>  4 files changed, 26 insertions(+), 31 deletions(-)

Both fixes look fine to me.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>